This invention relates to a 180.degree. folding tool bar and more particularly to a folding tool bar which has float capability and which eliminates free fall of the wing section as it is being pivotally moved between its field and transport positions.
Folding tool bars have for some time been used on agricultural implements to enable the width of the implement to be substantially reduced for transport purposes. For example, folding tool bars are described in U.S. Pat. Nos. 3,774,693; 3,941,194; and 4,074,766. In each of the tool bars of the foregoing patents, the wing sections are able to be pivoted to an upright position or approximately 90.degree. with respect to the main frame. Additionally, International Harvester is presently manufacturing an agricultural implement wherein the wing sections of the folding tool bar are pivoted 180.degree. with respect to the main frame.
In all of the agricultural implements employing a folding tool bar, a highly desirable feature is the ability of the wing sections to "float" with respect to the main frame so that the implement may conform to the contour of the ground. Obviously, if the wing section is to pivotally move upwardly and downwardly with respect to the main frame thereby achieving the desirable "float", some play or lost motion must be permitted in the pivotal connection between the hydraulic cylinder, which pivots the wing section, and the wing section to prevent the hydraulic fluid from being passed through the cylinder each time the wing section pivotally moves upwardly and downwardly during field operations. One method of providing the necessary pivotal connection between the hydraulic cylinder and the wing section is to have the rod end of the hydraulic cylinder received in a horizontally disposed slot in a linkage connecting the hydraulic cylinder and the wing section. Such a connection is described in U.S. Pat. No. 4,074,766. However, a problem is experienced in such a connection when the wing section is to be pivoted 180.degree. with respect to the main frame. This phenomenon is known as free fall and creates a very serious problem. During certain portions of the travel of the wing section between the transport and field positions, the rod end of the hydraulic cylinder moves in the slot within which it is received thereby causing the wing section to fall, out of control, for a certain amount of distance. The free fall of the wing section is not only dangerous to the operator but can severely damage the equipment.
Therefore, it is a principal object of the invention to provide an improved 180.degree. folding tool bar.
A further object of the invention is to provide a 180.degree. folding tool bar which permits the wing sections to float with respect to the main frame during field operations.
A still further object of the invention is to provide a folding 180.degree. tool bar which not only permits the wing sections to float but also prevents free fall of the wing section.
These and other objects will be apparent to those skilled in the art.